OTOY Forums

Karba , thanks for the idea of Fake glass thing !! I like this

Karba wrote:

gabrielefx wrote: In Octane you can't because it doesn't have an architectural specular mat.
Regards

Did you try to use glossy material with 100% reflection and falloff in opacity?

gabrielefx wrote: You can't simulate transparent thin walls with glossy mats because they are fake and you lost refractions on borders
Regards

What do you mean?

Hi Karba

yes I tried it but for me is not realistic by the fact that you haven't internal refractions.
Try to apply your example on a thin glass box. I need transparency and refraction.
In Vray-rt there is an option named "affect shadows".

Creating fake specular mats cause performance loss with glossy mats, try to apply a falloff node into a specular material and the performance will not be affected.

Regarding ies lights I could ring a light and a null point, for 100 emitters it's madness.
We can rotate with the gizmo of our lights but for precise position of targets we definitely need target point lights.

gabrielefx wrote:
Hi Karba

yes I tried it but for me is not realistic by the fact that you haven't internal refractions.
Try to apply your example on a thin glass box. I need transparency and refraction.
In Vray-rt there is an option named "affect shadows".

I know about that option. I have about 4years of vray experience. We will add thin option in future.
Can you show some of your vray renders, where you need refractions for thin glasses?

Karba wrote:

gabrielefx wrote:
Hi Karba

yes I tried it but for me is not realistic by the fact that you haven't internal refractions.
Try to apply your example on a thin glass box. I need transparency and refraction.
In Vray-rt there is an option named "affect shadows".

I know about that option. I have about 4years of vray experience. We will add thin option in future.
Can you show some of your vray renders, where you need refractions for thin glasses?

soon I will show you an example.
I always try to remove all glossy thin glass, when necessary I use the glossy specular fake mat but I never used the falloff option in transparency I used index forcing it when necessary.

@gabrielefx

A workarround to the lack of a real architetural glass is to setup a multi/sub material with a glossy transparent (opacity with falloff) material and a regular greenish glass specular meterial. By setting the polygon's ID, apply the specular one to the borders of your glass sheet and the glossy one to the front/back faces.

This way you get a fake architetural glass with darker refractive borders, but with correct alpha = no shadows.

adriano.ol wrote:@gabrielefx

A workarround to the lack of a real architetural glass is to setup a multi/sub material with a glossy transparent (opacity with falloff) material and a regular greenish glass specular meterial. By setting the polygon's ID, apply the specular one to the borders of your glass sheet and the glossy one to the front/back faces.

This way you get a fake architetural glass with darker refractive borders, but with correct alpha = no shadows.

good idea...
what about alpha channel on borders?

I need that the specular material hasn't to be affected by the double reflection issue.
Then I need 3 things:
specular mat has to show correct refractions
specular material has to be passed by sun light
specular material hasn't to show double reflections and distorted refractions when the opacity is on

Immagine a skyscraper with 1000 windows positioned on 3 layers, first layer is the real window, second is a colored glass skin where the borders are visible (no bezels), third layer is a photovoltaic structure
try to apply different ids on 3000 object that aren't oriented vertical horizontal...but all angled...
Then the final render has to be composited in photoshop putting a city background....
With massive use of glass materials today we can't use Octane.

Regards

gabrielefx wrote: what about alpha channel on borders?

As long as the borders are thin, alpha is not needed. Soft shadows for that area won't be visible at all. And even if they do, I think it is correct that borders in a flat glass project darker shadows.

But it's just a workaround because we still miss some refractions in the main faces.

Architectural glass is a must.

Yes we really need light passing through glass properly in octane.. It is quite a hassle to fake glass everytime and fake looking refractions.
The render posted by karba in this thread is missing a lot of light and thus bounces that should spill into the space from the strip of skylights above. There should be some sunlight hitting the floor beyond and even the hood of the car to make the render look more believable. not only the little bit we see on the floor on right

I did some work on materials and lighting
20 min of rendering on 1 GTX690
Path tracing kernel
max depth - 16
caustic blur - 1.0
max samples - 2500

Evermotion .I. //// 20 min ....... LOL
nice work KaRBa